The state of mind you're in when doing weed, drinking, or pretty much any kind of drugs. Many times at rock shows almost everyone goes to this insane world. This term was popularized by The Beatle's song 'Strawberry Fields.'
At a Led Zeppelin show in '76:
Guy: *pulls out weed* Hey brotha wanna go to this wonderful place called strawberry fields?
Guy 2: Where's that? I've never heard of it
Guy:Here take a puff of this and then you'll see why everyone wants to go there
Strawberry Jubbly Slide (v): intercourse between a man and a woman where the woman is on her period, but will not wear a any sort of feminine product (see beaver dam) prior to sex so as to use the oozing blood as lubrication. (See Chocolate Jubbly Slide)
Wife: Honey, let's get home soon because I think tonight you're gonna be riding the Strawberry Jubbly Slide!